813861 has 16 divisors (see below), whose sum is σ = 1235520. Its totient is φ = 529200.

The previous prime is 813847. The next prime is 813863. The reversal of 813861 is 168318.

813861 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 813861 - 2⁵ = 813829 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an Ulam number.

It is a Curzon number.

It is a plaindrome in base 15.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 813861.

It is not an unprimeable number, because it can be changed into a prime (813863) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 811 + ... + 1511.

It is an arithmetic number, because the mean of its divisors is an integer number (77220).

2⁸¹³⁸⁶¹ is an apocalyptic number.

It is an amenable number.

813861 is a deficient number, since it is larger than the sum of its proper divisors (421659).

813861 is a wasteful number, since it uses less digits than its factorization.

813861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 753 (or 747 counting only the distinct ones).

The product of its digits is 1152, while the sum is 27.

The square root of 813861 is about 902.1424499490. The cubic root of 813861 is about 93.3648518834.

The spelling of 813861 in words is "eight hundred thirteen thousand, eight hundred sixty-one".